Section (3) aio_read
aio_read — asynchronous read
||struct aiocb *aiocbp
queues the I/O request described by the buffer pointed to by
aiocbp. This function
is the asynchronous analog of read(2). The arguments of
read(fd, buf, count)
correspond (in order) to the fields
aio_nbytes of the structure pointed to by
aio(7) for a description of
the aiocb structure.)
The data is read starting at the absolute position
regardless of the file offset. After the call, the value of
the file offset is unspecified.
The asynchronous means that this call returns as soon as
the request has been enqueued; the read may or may not have
completed when the call returns. One tests for completion
using aio_error(3). The return
status of a completed I/O operation can be obtained by
notification of I/O completion can be obtained by setting
appropriately; see sigevent(7) for
defined, and this file supports it, then the asynchronous
operation is submitted at a priority equal to that of the
calling process minus
No data is read from a regular file beyond its maximum offset.
On success, 0 is returned. On error, the request is not
enqueued, −1 is returned, and
errno is set appropriately. If an error is
detected only later, it will be reported via aio_return(3) (returns
status −1) and aio_error(3) (error
status—whatever one would have gotten in
errno, such as EBADF).
Out of resources.
aio_fildesis not a valid file descriptor open for reading.
One or more of
aio_read() is not implemented.
The file is a regular file, we start reading before end-of-file and want at least one byte, but the starting position is past the maximum offset for this file.
For an explanation of the terms used in this section, see attributes(7).
It is a good idea to zero out the control block before use. The control block must not be changed while the read operation is in progress. The buffer area being read into must not be accessed during the operation or undefined results may occur. The memory areas involved must remain valid.
Simultaneous I/O operations specifying the same aiocb structure produce undefined results.
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Copyright (c) 2003 Andries Brouwer (aebcwi.nl)
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